290 NATURAL SCIENCE. Oct.. 



Besides the eleven species described above, there are three 

 which also move hygroscopically, but in a different way. 



These three, Hyptis pectinata, Elsholtzia cristata, and Nepda 

 hohamerica, have the axis of the calyx almost erect or else horizontal, 

 and the mouth not closed except by hairs, and in consequence of 

 wet the teeth close slightly. This movement is probably not 

 connected with the dispersal of seeds, but with their protection 

 from wet. 



1. Hyptis pectinata (Poit. ann. Mus.). 



The calyx is almost regular, campanulate, the mouth open, with 

 spreading pointed teeth. 



The flowers are arranged in cymes, which, when in fruit, are 

 elongated, unilateral and pectinate, with the calyx turned vertically 

 upwards. 



In wet the peduncles bend up so as to bring the calyces near the 

 main stem, and the calyx-teeth bend up so as to close the mouth. 



Habitat : Equinoctial America — dry chalky and sandy places. 

 Mexico, Tropical Africa, etc. 



2. Elsholtzia cristata (Willd). 



The flowers are in many-flowered verticillasters forming dense 

 unilateral spikes. The calyx, in fruit, is regular, campanulate, the 

 exterior hairy and glandular, the interior glabrous except for long 

 hairs on the margin of the teeth which almost close the mouth. The 

 axis of the calyx is horizontal or inclined upwards. 



In consequence of wet, the calyx-teeth close together partially. 



Habitat : Asia, and Europe introduced. 



3. Nepeta hohamerica (Regel). 



Stem erect branched. Flowers in terminal spikes. The calyx is 

 hairy and tubular, with sub-oblique mouth, the calyx-teeth lanceolate. 

 In consequence of wet, the calyx-teeth close slightly together. 



Habitat : Plains of Kohamyr. 



With the exception of the three last cases, the movements 

 described above appear to favour the dispersal of the nuts in rain, 

 yet it is not easy in every case to demonstrate this fact. In Lalle- 

 mantia, the nuts are far more easily shaken out in the wet condi- 

 tion, but in Ziziphova tenuior, which has similar movements, this was 

 not found to be the case. Possibly this may be due to the nuts not 

 being ripe. 



Salvia sclarea and Melissa officinalis have been placed with the 

 others, but their movements are so slight that it is difficult to see how 

 they can affect the dispersal of the nuts. In Ocimtim, too, although 

 the movement is very decided, yet the advantage gained is not 

 evident. 



In conclusion, I should like to express my thanks to Mr. F. 

 Darwin, for having suggested that I should examine Labiates in 

 regard ot the distribution of their seed, and also for his very kind 

 help and criticism. 



